DESCRIPTION The purpose of the proposed research program is to develop a general and efficient route to a structurally complex and biologically important molecule, norzoanthamine. Norzoanthamine hydrochloride suppresses the decrease in bone weight and strength in ovariectomized mice, which could make this compound a good candidate for an osteoporotic drug. Simple norzoanthamine analogues may retain anti-osteoporotic activity and allow easy preparation of potential osteoporotic drugs. Also, analogue preparation may provide valuable information on the biogenesis and mechanism of biological action of these compounds, since studies in these areas remain unexplored. Determining structure-activity relationships is crucial for understanding the mode of actions of norzoanthamine. Since norzoanthamine is isolated from the rare colonial zoanthid of these genus Zoanthus, only small amounts of sample can be obtained this way and it is for this reason that a total synthesis will also be quite beneficial.